1. Field of the Invention
The present invention relates generally to a pressurized liquid, load-bearing structure. More particularly, the present invention relates to column with a longitudinally expandable sleeve to contain a pressurized liquid.
2. Related Art
In mining it is often necessary to support the ceilings of tunnels and cavities to resist collapse. Various different methods have been proposed to prevent ceiling collapse. Traditional methods include wood or steel structures forming a framework to support the ceiling. Such wood or steel structures often become permanent due to the difficulty of removing them. In addition, the transportation of the necessary materials into the mine, and the construction of the framework, is often difficult and time consuming. Cement structures also have been proposed, but are difficult to use because the concrete must cure before accepting loads. In addition, unexpected loads can crush and destroy the forms before the concrete cures.